This is a note to let you know that I've just added the patch titled
net/xen-netback: prevent UAF in xenvif_flush_hash()
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
net-xen-netback-prevent-uaf-in-xenvif_flush_hash.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit d83d9852b3b3094f978f0d6d9ae19c8efcace4aa
Author: Jeongjun Park <aha310510@xxxxxxxxx>
Date: Fri Aug 23 03:11:09 2024 +0900
net/xen-netback: prevent UAF in xenvif_flush_hash()
[ Upstream commit 0fa5e94a1811d68fbffa0725efe6d4ca62c03d12 ]
During the list_for_each_entry_rcu iteration call of xenvif_flush_hash,
kfree_rcu does not exist inside the rcu read critical section, so if
kfree_rcu is called when the rcu grace period ends during the iteration,
UAF occurs when accessing head->next after the entry becomes free.
Therefore, to solve this, you need to change it to list_for_each_entry_safe.
Signed-off-by: Jeongjun Park <aha310510@xxxxxxxxx>
Link: https://patch.msgid.link/20240822181109.2577354-1-aha310510@xxxxxxxxx
Signed-off-by: Jakub Kicinski <kuba@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/net/xen-netback/hash.c b/drivers/net/xen-netback/hash.c
index ff96f22648efd..45ddce35f6d2c 100644
--- a/drivers/net/xen-netback/hash.c
+++ b/drivers/net/xen-netback/hash.c
@@ -95,7 +95,7 @@ static u32 xenvif_new_hash(struct xenvif *vif, const u8 *data,
static void xenvif_flush_hash(struct xenvif *vif)
{
- struct xenvif_hash_cache_entry *entry;
+ struct xenvif_hash_cache_entry *entry, *n;
unsigned long flags;
if (xenvif_hash_cache_size == 0)
@@ -103,8 +103,7 @@ static void xenvif_flush_hash(struct xenvif *vif)
spin_lock_irqsave(&vif->hash.cache.lock, flags);
- list_for_each_entry_rcu(entry, &vif->hash.cache.list, link,
- lockdep_is_held(&vif->hash.cache.lock)) {
+ list_for_each_entry_safe(entry, n, &vif->hash.cache.list, link) {
list_del_rcu(&entry->link);
vif->hash.cache.count--;
kfree_rcu(entry, rcu);
